1. Field of the Invention
The present invention relates to an image forming system for forming images.
2. Description of the Prior Art
In prior art copying machines of the type, a light source is caused to scan along the original surface and close to the original, an optical system including the light source has been moved, and when stopping at a specified position, its speed has been slowed down by a frictional force of a wire, rail, or the like supporting the optical system by cutting off the driving force before the stop position, or typically a damper has been provided at the stop position to stop the motion.
However, as the copying speed of the copying machine has been increased to high speeds, it has been difficult for the prior art method to give stable stop position not only in copying machines but in any other equipment causing a moving body to move at high speeds, and inability to give a stable stop position has been a common problem.
In addition, copying machines of the prior art having an optical system scanning means including a light source which scans the original and is capable of changing the copy magnification, the optical system has performed the original scan of a constant width regardless of the sheet size of the transfer sheet. The processing speed of this method, however, has been slow due to wasteful scan by the optical scan means .
There is also a system wherein only the effective range of the copy sheet is scanned using a plurality of inversion filters. However, this method has a drawback that in copying machines capable of changing the copy magnification continuously or capable of setting at many copy magnifications, number of inversion sensors must be provided with resultant complicated structure and complex control.
In addition, in prior art copying machines, the control sequence of typically continuous copy has been performed based on typically a driving clock of the transfer means, and the next transfer sheet feed operation has been performed at the inverse timing of the original scan system, or typically by a position sensor of the optical system.
As a result, in copying machines wherein the magnification is settable continuously, the scan timing has changed each time, with the resultant complicated sequence control, particularly, complex feed/scan timing control in the sequential copy mode. In addition, when a plurality of sheet feed means are provided, separate control for each sheet feed means has been necessary, thereby making the control very complex.
In addition, in prior art copying machines, display items at a numeric display unit have been limited typically to the set value of the number of copies, the number of copies obtained, and magnification.
In addition, in prior art display units, display information has been sent to the display unit only when the content to be displayed on the display unit has changed. However, this method has such problem that when noise is applied onto the data bus to which information is to be sent and the effect of this noise cannot be removed, the true display content and actual display content would differ.